A versatile noun meaning the back or upper side of something — the curved surface, the boss of a shield, the rim of a wheel, or the vault of the sky. It conveys the idea of height, curvature, and the underside of the celestial canopy.
Gab carries cosmological weight when it refers to the vault or arch of the heavens — the dome-like canopy the Hebrews understood as the sky. In Ezekiel's vision of the wheels, gab describes the rims of the great wheels full of eyes (Ezekiel 1:18; 10:12). The curvature of the back, the boss of a shield, the arch of the sky — all speak of God's overarching sovereignty. He spans the heavens as a craftsman spans a measurement. The vault above is not an accident; it is the handiwork of the One who stretched out the heavens like a tent (Psalm 104:2).